LeetCode *** 113. Path Sum II

题目：

Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example:

Given the below binary tree and

sum = 22

,

5
/ \
4   8
/   / \
11  13  4
/  \    / \
7    2  5   1

return

[
[5,4,11,2],
[5,8,4,5]
]

分析：

不要自以为是的添加一些限制条件。

代码：

/**
* Definition for a binary tree node.
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
vector<vector<int>> res;
int s;
vector<vector<int>> pathSum(TreeNode* root, int sum) {
if(root==NULL)return res;
s=sum;
vector<int> t;
dfs(root,t,0);
return res;
}

void dfs(TreeNode* root,vector<int> tmp,int sum){
tmp.push_back(root->val);
sum+=root->val;
if(!root->left&&!root->right&&sum==s){
res.push_back(tmp);
}
else {
if(root->left)
dfs(root->left,tmp,sum);
if(root->right)
dfs(root->right,tmp,sum);
}
}

};